Remove fomantic accordion module (#15951)

Replace it with native <detail> element. Did some slight restyling on
the release downloads, new behaviour should be exactly the same
otherwise.

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

web_src/less/_base.less

@@ -164,6 +164,14 @@ table {
   border-collapse: collapse;
 }
 
+details summary {
+  cursor: pointer;
+}
+
+details summary > * {
+  display: inline;
+}
+
 * {
   scrollbar-width: thin;
   scrollbar-color: var(--color-primary) transparent;